Hydrothermally grown synthetic rubies crystallize slowly out of a solution (a mix of water and dissolved elements) that has been exposed to heat and pressure similar to the conditions on Earth under which the natural gem mineral grows. Synthetic gems have the same chemical, optical, and physical properties of their natural counterparts, but are a more cost-effective alternative to a natural gem.

Alternate
Names

Lab Created Ruby

Colors

Slightly Orangy Red, Red, Purplish Red

Ruby (Synthetic - Hydrothermal) Classification

Common Name

Ruby (Synthetic - Hydrothermal)

Species

Corundum

Variety

Hydrothermal Synthetic Ruby

Colors

Slightly Orangy Red, Red, Purplish Red

Alternate Names

Lab Created Ruby

Gemstone Groups

Key Separations

magnification and RI, birefringence, pleochroism

Comments

Ruby (Synthetic - Hydrothermal) Optical Properties

Transparency

Transparent - Opaque

Refractive Index

1.762-1.77 Tolerance:(+0.009/-0.005)

Birefringence

0.008-0.01

Optic Character

Uniaxial

Optic Sign

Negative

Polariscope Reaction

Doubly Refractive (DR)

Fluorescence

SWUV: inert to weak red LWUV: weak to moderate red

CCF Reaction

red

Pleochroism

Dichroic, moderate to strong orangy red and purplish red

Dispersion

Strength: moderate fire Value: 0.018

Comments

Ruby (Synthetic - Hydrothermal) Chemistry & Crystallography

Chemical Name

aluminum oxide

Chemical Formula

Al2O3

Synthesis

hydrothermal

Crystal System

Trigonal

Classification

Oxide

Nature

Synthetic

Crystallinity

Crystalline

Comments

Ruby (Synthetic - Hydrothermal) Characteristic Physical Properties

Hardness

9

Streak

White

Specific Gravity

3.95-4.1 Typical:4

Toughness

Excellent

Inclusions

Look for chevron, wavy, zig-zag or mosaic growth patterns in hydrothermal synthetic ruby because stones might show growth zoning similar to natural ruby. Fingerprint like inclusions with 2-phase and 3-phase inclusions can be seen in stones. Sometimes flake like copper inclusions are visible in reflected light.